syndicate-rs/src/actor.rs

596 lines
19 KiB
Rust

pub use futures::future::BoxFuture;
pub use std::future::ready;
use super::ActorId;
use super::schemas::internal_protocol::*;
use super::error::Error;
use super::error::error;
use preserves::value::Domain;
use preserves::value::IOValue;
use preserves::value::Map;
use preserves::value::NestedValue;
use std::boxed::Box;
use std::collections::hash_map::HashMap;
use std::sync::Arc;
use std::sync::atomic::{AtomicUsize, Ordering};
use tokio::select;
use tokio::sync::mpsc::{unbounded_channel, UnboundedSender, UnboundedReceiver};
use tokio_util::sync::CancellationToken;
use tracing;
use tracing::Instrument;
pub type Assertion = super::schemas::dataspace::_Any;
pub use super::schemas::internal_protocol::Handle;
pub use super::schemas::internal_protocol::Oid;
pub type ActorResult = Result<(), Error>;
pub type ActorHandle = tokio::task::JoinHandle<ActorResult>;
pub trait Entity: Send {
fn assert(&mut self, _t: &mut Activation, _a: Assertion, _h: Handle) -> ActorResult {
Ok(())
}
fn retract(&mut self, _t: &mut Activation, _h: Handle) -> ActorResult {
Ok(())
}
fn message(&mut self, _t: &mut Activation, _m: Assertion) -> ActorResult {
Ok(())
}
fn sync(&mut self, t: &mut Activation, peer: Arc<Ref>) -> ActorResult {
t.message(&peer, Assertion::new(true));
Ok(())
}
fn turn_end(&mut self, _t: &mut Activation) -> ActorResult {
Ok(())
}
fn exit_hook(&mut self, _t: &mut Activation, _exit_status: &ActorResult) -> BoxFuture<ActorResult> {
Box::pin(ready(Ok(())))
}
}
enum Destination {
ImmediateSelf(Oid),
Remote(Arc<Ref>),
}
type OutboundAssertions = Map<Handle, Destination>;
type PendingEventQueue = Vec<(Arc<Ref>, Event)>;
// This is what other implementations call a "Turn", renamed here to
// avoid conflicts with schemas::internal_protocol::Turn.
pub struct Activation<'activation> {
pub actor: &'activation mut Actor,
queues: HashMap<ActorId, PendingEventQueue>,
immediate_self: Vec<TurnEvent>,
}
#[derive(Debug)]
enum SystemMessage {
Release,
ReleaseOid(Oid),
Turn(Turn),
Crash(Error),
}
pub struct Mailbox {
pub actor_id: ActorId,
pub mailbox_id: u64,
tx: UnboundedSender<SystemMessage>,
queue_depth: Arc<AtomicUsize>,
mailbox_count: Arc<AtomicUsize>,
}
pub struct Actor {
actor_id: ActorId,
tx: UnboundedSender<SystemMessage>,
rx: UnboundedReceiver<SystemMessage>,
queue_depth: Arc<AtomicUsize>,
mailbox_count: Arc<AtomicUsize>,
outbound_assertions: OutboundAssertions,
oid_map: Map<Oid, Box<dyn Entity + Send>>,
next_task_id: u64,
linked_tasks: Map<u64, CancellationToken>,
exit_hooks: Vec<Oid>,
}
#[derive(PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct Ref {
pub relay: Mailbox,
pub target: Oid,
/* TODO: attenuation */
}
//---------------------------------------------------------------------------
preserves_schema::support::lazy_static! {
pub static ref INERT_REF: Arc<Ref> = {
struct InertEntity;
impl crate::actor::Entity for InertEntity {}
let mut ac = Actor::new();
let e = ac.create(InertEntity);
ac.boot(tracing::info_span!(parent: None, "INERT_REF"),
|t| Box::pin(ready(Ok(t.actor.shutdown()))));
e
};
}
impl<'activation> Activation<'activation> {
pub fn for_actor(actor: &'activation mut Actor) -> Self {
Activation {
actor,
queues: HashMap::new(),
immediate_self: Vec::new(),
}
}
fn immediate_oid(&self, r: &Arc<Ref>) -> Oid {
if r.relay.actor_id != self.actor.actor_id {
panic!("Cannot use immediate_self to send to remote peers");
}
r.target.clone()
}
pub fn assert<M>(&mut self, r: &Arc<Ref>, a: M) -> Handle where M: Into<Assertion> {
let handle = crate::next_handle();
self.queue_for(r).push((Arc::clone(r), Event::Assert(Box::new(
Assert { assertion: Assertion(a.into()), handle: handle.clone() }))));
self.actor.outbound_assertions.insert(handle.clone(), Destination::Remote(Arc::clone(r)));
handle
}
pub fn assert_immediate_self<M>(&mut self, r: &Arc<Ref>, a: M) -> Handle where M: Into<Assertion> {
let oid = self.immediate_oid(r);
let handle = crate::next_handle();
self.immediate_self.push(TurnEvent {
oid: oid.clone(),
event: Event::Assert(Box::new(
Assert { assertion: Assertion(a.into()), handle: handle.clone() })),
});
self.actor.outbound_assertions.insert(handle.clone(), Destination::ImmediateSelf(oid));
handle
}
pub fn retract(&mut self, handle: Handle) {
if let Some(d) = self.actor.outbound_assertions.remove(&handle) {
self.retract_known_ref(d, handle)
}
}
fn retract_known_ref(&mut self, d: Destination, handle: Handle) {
match d {
Destination::Remote(r) =>
self.queue_for(&r).push((r, Event::Retract(Box::new(Retract { handle })))),
Destination::ImmediateSelf(oid) =>
self.immediate_self.push(TurnEvent {
oid,
event: Event::Retract(Box::new(Retract { handle })),
}),
}
}
pub fn message<M>(&mut self, r: &Arc<Ref>, m: M) where M: Into<Assertion> {
self.queue_for(r).push((Arc::clone(r), Event::Message(Box::new(
Message { body: Assertion(m.into()) }))))
}
pub fn message_immediate_self<M>(&mut self, r: &Arc<Ref>, m: M) where M: Into<Assertion> {
self.immediate_self.push(TurnEvent {
oid: self.immediate_oid(r),
event: Event::Message(Box::new(Message { body: Assertion(m.into()) })),
})
}
pub fn sync(&mut self, r: &Arc<Ref>, peer: Arc<Ref>) {
self.queue_for(r).push((Arc::clone(r), Event::Sync(Box::new(Sync { peer }))));
}
fn queue_for(&mut self, r: &Arc<Ref>) -> &mut PendingEventQueue {
self.queues.entry(r.relay.actor_id).or_default()
}
fn deliver(&mut self) {
if !self.immediate_self.is_empty() {
panic!("Unprocessed immediate_self events remain at deliver() time");
}
for (_actor_id, turn) in std::mem::take(&mut self.queues).into_iter() {
if turn.len() == 0 { continue; }
let first_ref = Arc::clone(&turn[0].0);
let target = &first_ref.relay;
target.send(Turn(turn.into_iter().map(
|(r, e)| TurnEvent { oid: r.target.clone(), event: e }).collect()));
}
}
fn with_oid<R,
Ff: FnOnce(&mut Self) -> R,
Fs: FnOnce(&mut Self, &mut Box<dyn Entity + Send>) -> R>(
&mut self,
oid: &Oid,
kf: Ff,
ks: Fs,
) -> R {
match self.actor.oid_map.remove_entry(&oid) {
None => kf(self),
Some((k, mut e)) => {
let result = ks(self, &mut e);
self.actor.oid_map.insert(k, e);
result
}
}
}
}
impl<'activation> Drop for Activation<'activation> {
fn drop(&mut self) {
self.deliver()
}
}
impl Mailbox {
pub fn send(&self, t: Turn) {
let _ = self.tx.send(SystemMessage::Turn(t));
self.queue_depth.fetch_add(1, Ordering::Relaxed);
}
}
impl std::fmt::Debug for Mailbox {
fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
write!(f, "#<Mailbox {}:{}>", self.actor_id, self.mailbox_id)
}
}
impl std::hash::Hash for Mailbox {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
self.mailbox_id.hash(state)
}
}
impl Eq for Mailbox {}
impl PartialEq for Mailbox {
fn eq(&self, other: &Mailbox) -> bool {
self.mailbox_id == other.mailbox_id
}
}
impl Ord for Mailbox {
fn cmp(&self, other: &Mailbox) -> std::cmp::Ordering {
return self.mailbox_id.cmp(&other.mailbox_id)
}
}
impl PartialOrd for Mailbox {
fn partial_cmp(&self, other: &Mailbox) -> Option<std::cmp::Ordering> {
return Some(self.cmp(&other))
}
}
impl Clone for Mailbox {
fn clone(&self) -> Self {
let Mailbox { actor_id, tx, queue_depth, mailbox_count, .. } = self;
let _old_refcount = mailbox_count.fetch_add(1, Ordering::SeqCst);
let new_mailbox = Mailbox {
actor_id: *actor_id,
mailbox_id: crate::next_mailbox_id(),
tx: tx.clone(),
queue_depth: Arc::clone(queue_depth),
mailbox_count: Arc::clone(mailbox_count),
};
// tracing::trace!(old_mailbox = debug(&self),
// new_mailbox = debug(&new_mailbox),
// new_mailbox_refcount = debug(_old_refcount + 1));
new_mailbox
}
}
impl Drop for Mailbox {
fn drop(&mut self) {
let old_mailbox_refcount = self.mailbox_count.fetch_sub(1, Ordering::SeqCst);
let new_mailbox_refcount = old_mailbox_refcount - 1;
// tracing::trace!(mailbox = debug(&self),
// new_mailbox_refcount);
if new_mailbox_refcount == 0 {
let _ = self.tx.send(SystemMessage::Release);
()
}
}
}
impl Actor {
pub fn new() -> Self {
let (tx, rx) = unbounded_channel();
let actor_id = crate::next_actor_id();
// tracing::trace!(id = actor_id, "Actor::new");
Actor {
actor_id,
tx,
rx,
queue_depth: Arc::new(AtomicUsize::new(0)),
mailbox_count: Arc::new(AtomicUsize::new(0)),
outbound_assertions: Map::new(),
oid_map: Map::new(),
next_task_id: 0,
linked_tasks: Map::new(),
exit_hooks: Vec::new(),
}
}
pub fn create_and_start<E: Entity + Send + 'static>(name: tracing::Span, e: E) -> Arc<Ref> {
Self::create_and_start_rec(name, e, |_, _, _| ())
}
pub fn create_and_start_rec<E: Entity + Send + 'static,
F: FnOnce(&mut Self, &mut E, &Arc<Ref>) -> ()>(
name: tracing::Span,
e: E,
f: F,
) -> Arc<Ref> {
let mut ac = Self::new();
let r = ac.create_rec(e, f);
ac.start(name);
r
}
pub fn id(&self) -> ActorId {
self.actor_id
}
fn mailbox(&mut self) -> Mailbox {
let _old_refcount = self.mailbox_count.fetch_add(1, Ordering::SeqCst);
let new_mailbox = Mailbox {
actor_id: self.actor_id,
mailbox_id: crate::next_mailbox_id(),
tx: self.tx.clone(),
queue_depth: Arc::clone(&self.queue_depth),
mailbox_count: Arc::clone(&self.mailbox_count),
};
// tracing::trace!(new_mailbox = debug(&new_mailbox),
// new_mailbox_refcount = debug(_old_refcount + 1));
new_mailbox
}
pub fn shutdown(&mut self) {
let _ = self.tx.send(SystemMessage::Release);
()
}
pub fn create<E: Entity + Send + 'static>(&mut self, e: E) -> Arc<Ref> {
self.create_rec(e, |_, _, _| ())
}
pub fn create_rec<E: Entity + Send + 'static,
F: FnOnce(&mut Self, &mut E, &Arc<Ref>) -> ()>(
&mut self,
mut e: E,
f: F,
) -> Arc<Ref> {
let oid = crate::next_oid();
let r = Arc::new(Ref { relay: self.mailbox(), target: oid.clone() });
f(self, &mut e, &r);
self.oid_map.insert(oid, Box::new(e));
r
}
pub fn boot<F: 'static + Send + for<'a> FnOnce(&'a mut Activation) -> BoxFuture<'a, ActorResult>>(
mut self,
name: tracing::Span,
boot: F,
) -> ActorHandle {
name.record("actor_id", &self.id());
tokio::spawn(async move {
tracing::trace!("start");
let result = self.run(boot).await;
{
let mut t = Activation::for_actor(&mut self);
for oid in std::mem::take(&mut t.actor.exit_hooks) {
match t.actor.oid_map.remove_entry(&oid) {
None => (),
Some((k, mut e)) => {
if let Err(err) = e.exit_hook(&mut t, &result).await {
tracing::error!(err = debug(err),
oid = debug(oid),
"error in exit hook");
}
t.actor.oid_map.insert(k, e);
}
}
}
}
match &result {
Ok(()) => {
tracing::trace!("normal stop");
()
}
Err(e) => tracing::error!("error stop: {}", e),
}
result
}.instrument(name))
}
pub fn start(self, name: tracing::Span) -> ActorHandle {
self.boot(name, |_ac| Box::pin(ready(Ok(()))))
}
async fn run<F: 'static + Send + for<'a> FnOnce(&'a mut Activation) -> BoxFuture<'a, ActorResult>>(
&mut self,
boot: F,
) -> ActorResult {
let _id = self.id();
// tracing::trace!(_id, "boot");
boot(&mut Activation::for_actor(self)).await?;
// tracing::trace!(_id, "run");
loop {
match self.rx.recv().await {
None =>
Err(error("Unexpected channel close", _Any::new(false)))?,
Some(m) => {
let should_stop = self.handle(m).await?;
if should_stop {
return Ok(());
}
// We would have a loop calling try_recv until it answers "no more at
// present" here, to avoid decrementing queue_depth for every message
// (instead zeroing it on queue empty - it only needs to be approximate),
// but try_recv has been removed from mpsc at the time of writing. See
// https://github.com/tokio-rs/tokio/issues/3350 . (***)
}
}
}
}
pub fn add_exit_hook(&mut self, oid: &Oid) {
self.exit_hooks.push(oid.clone())
}
async fn handle(&mut self, m: SystemMessage) -> Result<bool, Error> {
match m {
SystemMessage::Release => {
tracing::trace!("SystemMessage::Release");
Ok(true)
}
SystemMessage::ReleaseOid(oid) => {
tracing::trace!("SystemMessage::ReleaseOid({:?})", &oid);
self.oid_map.remove(&oid);
Ok(false)
}
SystemMessage::Turn(Turn(mut events)) => {
let mut t = Activation::for_actor(self);
loop {
for TurnEvent { oid, event } in events.into_iter() {
t.with_oid(&oid, |_| Ok(()), |t, e| match event {
Event::Assert(b) => {
let Assert { assertion: Assertion(assertion), handle } = *b;
e.assert(t, assertion, handle)
}
Event::Retract(b) => {
let Retract { handle } = *b;
e.retract(t, handle)
}
Event::Message(b) => {
let Message { body: Assertion(body) } = *b;
e.message(t, body)
}
Event::Sync(b) => {
let Sync { peer } = *b;
e.sync(t, peer)
}
})?;
}
events = std::mem::take(&mut t.immediate_self);
if events.is_empty() { break; }
}
t.actor.queue_depth.fetch_sub(1, Ordering::Relaxed); // see (***) in this file
Ok(false)
}
SystemMessage::Crash(e) => {
tracing::trace!("SystemMessage::Crash({:?})", &e);
Err(e)?
}
}
}
pub fn linked_task<F: futures::Future<Output = ActorResult> + Send + 'static>(
&mut self,
name: tracing::Span,
boot: F,
) {
let mailbox = self.mailbox();
let token = CancellationToken::new();
let task_id = self.next_task_id;
self.next_task_id += 1;
name.record("task_id", &task_id);
{
let token = token.clone();
tokio::spawn(async move {
tracing::trace!(task_id, "linked task start");
select! {
_ = token.cancelled() => {
tracing::trace!(task_id, "linked task cancelled");
Ok(())
}
result = boot => {
match &result {
Ok(()) => {
tracing::trace!(task_id, "linked task normal stop");
()
}
Err(e) => {
tracing::error!(task_id, "linked task error: {}", e);
let _ = mailbox.tx.send(SystemMessage::Crash(e.clone()));
()
}
}
result
}
}
}.instrument(name));
}
self.linked_tasks.insert(task_id, token);
}
}
impl Drop for Actor {
fn drop(&mut self) {
for (_task_id, token) in std::mem::take(&mut self.linked_tasks).into_iter() {
token.cancel();
}
let to_clear = std::mem::take(&mut self.outbound_assertions);
let mut t = Activation::for_actor(self);
for (handle, r) in to_clear.into_iter() {
tracing::trace!(h = debug(&handle), "retract on termination");
t.retract_known_ref(r, handle);
}
tracing::trace!("Actor::drop");
}
}
impl Ref {
pub fn external_event(&self, event: Event) {
self.relay.send(Turn(vec![TurnEvent { oid: self.target.clone(), event }]))
}
}
impl std::fmt::Debug for Ref {
fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
write!(f, "⌜{}:{}⌝", self.relay.actor_id, self.target.0)
}
}
impl Drop for Ref {
fn drop(&mut self) {
let _ = self.relay.tx.send(SystemMessage::ReleaseOid(self.target.clone()));
()
}
}
impl Domain for Ref {}
impl std::convert::TryFrom<&IOValue> for Ref {
type Error = preserves_schema::support::ParseError;
fn try_from(_v: &IOValue) -> Result<Self, Self::Error> {
panic!("Attempted to serialize Ref via IOValue");
}
}
impl std::convert::From<&Ref> for IOValue {
fn from(_v: &Ref) -> IOValue {
panic!("Attempted to deserialize Ref via IOValue");
}
}
#[macro_export]
macro_rules! name {
() => {tracing::info_span!(actor_id = tracing::field::Empty,
task_id = tracing::field::Empty,
oid = tracing::field::Empty)};
($($item:tt)*) => {tracing::info_span!($($item)*,
actor_id = tracing::field::Empty,
task_id = tracing::field::Empty,
oid = tracing::field::Empty)}
}